Lecture 28 Flashcards
How much of the male human body is water?
60%
How much of the female human body is water?
55%
Why do biological males store more water than biological females?
Males carry more muscle mass which as a higher water content in comparison to the higher adipose mass that females carry
How does the urinary system maintain a balance?
By filtering the blood and expelling anything we don’t need
What might be expelled in urine?
Excess water and salt, waste of metabolism and toxins or drugs
How much blood flows through the kidneys per minute?
1200mL
How much urine does the typical person produce per day?
800-2000mL
What is urine?
A waste product excreted to maintain balance within the body
What does normal urine contain?
Water, salts, urea, metabolites, hormones and small proteins
What is the normal pH range for urine?
~4.6-8
What can abnormal urine contain?
Large proteins or RBC, as they are too big to be filtered or glucose that is filtered by completely reabsorbed
To be effective, what does the urinary system need?
Blood delivery, selective filtration and filtrate removal systems, filtrate recovery mechanism, system to return recovered filtered fluid to the body, protection, communication and adaptability
What are the main components of the urinary system?
2 kidneys, 2 ureters, urinary bladder and a urethra
What is a ureter?
Straw-like tube connecting kidneys to the urinary bladder
What is the urethra?
The tube that lets urine leave your bladder and your body
What does the structure of the kidneys allow?
Blood to be brought near the nephron for filtering; filtered blood to leave the kidney; a path for urine to be removed from the kidney, stored and excreted; protection
Where do the kidneys sit?
Deep to the T12 and L3 vertebrae, between the 11th and 12th rib
Why is the right kidney slightly lower than the left?
To accommodate for the liver
What surface of the kidney faces laterally?
Convex
What is on the medial surface of the kidney?
A concave notch called the hilum
What is a hilum?
The part of an organ where systems enter and exit
What is within the kidneys hilum?
Renal blood vessels, lymphatics, nerves and the ureter
The kidneys are…?
Retroperitoneal, anterior surface covered with peritoneum, posterior surface on abdominal wall
What are the three structures that provide external protection for the kidneys?
11th and 12th rib, renal fat pad, fibrous capsule
What are the three regions of the kidney?
Cortex, medullar and pelvis
What is the cortex of the kidney?
Outer: a continuous layer containing renal columns
What is the medullar of the kidney?
Inner: divided into pyramids, each ending in a papilla
What do the cortex and medulla combined form?
A kidney lobe, functional unit
How many kidney lobes are the per kidney?
5-11
What does a kidney lobe contain?
One medullary pyramid, all the surrounding cortex, with thousands of nephrons
What is the urine drainage path from the kidneys?
From each papilla, collecting in the minor calyx, to the major calyx which join to form the renal pelvis that exits the hilum to become the ureter
How is urine produced?
By filtering waste from the blood into the nephron
Where does filtration occur?
In the cortex of the kidney
Where does the renal artery arise from?
The abdominal aorta
Where does filtered blood go?
To the veins from the cortex, to the renal vein then the inferior vena cava
What is the glomerulus?
A bundle of capillaries specialised for filtration
What supplies the glomerulus?
The afferent arteriole
Where does blood leave the glomerulus?
Via the efferent arteriole
What does the efferent arteriole supply?
The peritubular capillaries
What do the peritubular capillaries do?
Carry the filtered blood to the veins
What is the flow of blood into the cortex?
Abdominal aorta → renal artery → series of arteries → afferent arteriole → glomerular capillary
What is the flow of blood away from the cortex?
Glomerular capillary → efferent arteriole → peritubular capillaries → series of veins → renal vein→ inferior vena cava
What is the nerve supply of the urinary system?
Innervation from a network of autonomic nerves and ganglia called the renal plexus
What type of nerves adjust the diameter of renal arterioles?
Sympathetic nerves
Why does the diameter of renal arterioles need to be controled?
To regulate blood flow
What is the nephron?
A microscopic functional unit making up the bulk of the kidney
What does the nephron do?
Filters blood to selectively reabsorb or secrete it and produce urine
What is the renal corpuscle?
Where the vessels enter the glomerulus
What is the name for filtered blood?
Filtrate
What is the function of the PCT?
Reabsorbing glomerular filtrate
What is the function of the nephron loop?
Water and salt reabsorption
What is the collecting duct?
A duct shared by many DCTs that regulates reabsorption of filtrate if the body needs it. Under hormonal control
